This invention relates to an apparatus for controlling movement of a throttle valve in response to a change in the position of an accelerator and, more particularly, to a throttle valve control apparatus which can limit the speed of movement of the throttle valve below an upper limit determined in accordance with transmission gear position.
In order to meter the amount of air to an internal combustion engine, a variable positionable throttle valve is situated within the induction passage of the engine. Normally, a mechanical link mechanism is provided to couple the throttle valve to an accelerator pedal in a manner to move the throttle valve in response to movement of the accelerator pedal. In order to control the throttle valve in a special fashion in response to movement of the accelerator pedal, it has been proposed to substitute an electrical servo control system for the mechanical link mechanism. Such an electrical servo control system includes a potentiometer which converts the movement of the accelerator pedal into a corresponding electric signal which is electrically processed to drive an actuator which thereby moves the throttle valve to a position corresponding to the new position of the accelerator pedal.
The engine produces an output torque which is adjusted under the control of the throttle valve. The engine output torque is transmitted from a flywheel to a plurality of driving wheels through a wheel driving system. The driving system includes a transmission having a plurality of gears which are selectively engageable between a driven shaft and a drive shaft. The driven shaft is coupled through a clutch device to the flywheel. The drive shaft is coupled to a differential gear which divides the transmitted torque to the driving wheels. The engine output torque is transmitted to the driving system along with engine vibrations having a component produced upon a rapid movement of the throttle valve. If the vibration component has a frequency generally equal to the characteristic frequency of the driving system, the driving device will vibrate greatly, causing the vehicle to pitch.
Accordingly, it is the problem in the art to provide a throttle valve control apparatus which can control the throttle valve without resonance of the driving system with respect to engine vibrations.